The shop manual does not have a really good drawing of the "fast idle vacuum power unit" on the carburetor for the 1963 390 V-8 for the Eldorado Biarritz (Im not sure if it is different from the other Cadillacs of that year).
It would be great if owners of the Biarritz (and other Cadillacs, if the engine is the same) for that year would take pictures of the carb, a top view, 3 side views (front, left and right) and a close up of the fast idle vacuum power unit. You can send digital photos to rob88roth@comcast.net. If you want to mail me photos, let me know and I will give you my address.
Thanks, Rob Roth